Conventionally, for example, a limit switch disclosed in JP 11-238430 A is well known as this kind of limit switch. The limit switch disclosed in JP 11-238430 A is one called a roller arm type.
As illustrated in FIGS. 9A, 9B, and 10, in a limit switch 100 disclosed in JP 11-238430 A, an actuator 103 is coupled to one end of a main shaft 102 supported in a container body 101, and a roller 104 that is in contact with a detected object is attached to a leading end of the actuator 103. The detected object abuts on the roller 104 to turn the actuator 103 together with the main shaft 102, and a cam 105 coupled to the main shaft 102 is turned together with the main shaft 102 in the container body 101. A plunger 107 includes a cam follower 106 that is located at a leading end of the plunger 107 to abut on a circumferential surface of the cam 105, whereby the plunger 107 moves linearly. The plunger 107 is coupled to an operating shaft 109 of a built-in switch 108 in which a contact is opened and closed by a pressing operation. When the plunger 107 moves linearly in association with the turning of the cam 105, the operating shaft 109 is pressed to open and close the built-in switch 108.